Gold nanoparticle-polymer nanocomposites synthesized by room temperature atmospheric pressure plasma and their potential for fuel cell electrocatalytic application

Conductive polymers have been increasingly used as fuel cell catalyst support due to their electrical conductivity, large surface areas and stability. The incorporation of metal nanoparticles into a polymer matrix can effectively increase the specific surface area of these materials and hence improve the catalytic efficiency. In this work, a nanoparticle loaded conductive polymer nanocomposite was obtained by a one-step synthesis approach based on room temperature direct current plasmaliquid interaction. Gold nanoparticles were directly synthesized from HAuCl4 precursor in poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT: PSS). The resulting AuNPs/PEDOT: PSS nanocomposites were subsequently characterized under a practical alkaline direct ethanol fuel cell operation condition for its potential application as an electrocatalyst. Results show that AuNPs sizes within the PEDOT: PSS matrix are dependent on the plasma treatment time and precursor concentration, which in turn affect the nanocomposites electrical conductivity and their catalytic performance. Under certain synthesis conditions, unique nanoscale AuNPs/PEDOT: PSS core-shell structures could also be produced, indicating the interaction at the AuNPs/polymer interface. The enhanced catalytic activity shown by AuNPs/PEDOT: PSS has been attributed to the effective electron transfer and reactive species diffusion through the porous polymer network, as well as the synergistic interfacial interaction at the metal/polymer and metal/metal interfaces.Funding Agencies|UK EPSRC [EP/K022237/1, EP/M024938/1, EP/P00394X/1, EP/I013229/1]; National Natural Science Foundation of China [51203135]; InvestNI [PoC-325]; Department of Employment Learning; EU-COST Action [TD1208]</p

Police-initiated diversion for youth to prevent future delinquent behavior: a systematic review

BackgroundOverly punitive responses to youth misconduct may have the unintended consequence ofincreasing the likelihood of future delinquency; yet, overly lenient responses may fail to serveas a corrective for the misbehavior. Police diversion schemes are a collection of strategiespolice can apply as an alternative to court processing of youth. Police-initiated diversionschemes aim to reduce reoffending by steering youth away from deeper penetration into thecriminal justice system and by providing an alternative intervention that can help youthaddress psychosocial development or other needs that contribute to their problem behavior.ObjectivesThe objective of this review was to synthesize the evidence on the effectiveness of pre-courtinterventions involving police warning or counseling and release, and cautioning schemes inreducing delinquent behavior.Search methodsA combination of 26 databases and websites were searched. References of relevant reviewswere also scanned to identify studies. We also consulted with experts in the field. Searcheswere executed by two reviewers and conducted between August 2016 and January 2017.Selection criteriaOnly experimental and quasi-experimental designs were eligible for this review. All quasiexperimentaldesigns must have had a comparison group similar to the police diversionintervention group with respect to demographic characteristics and prior involvement indelinquent behavior (i.e., at similar risk for future delinquent behavior). Additionally, studiesmust have included youth participants between 12 and 17 years of age who either underwenttraditional system processing or were diverted from court processing through a police-leddiversion program. Studies were also eligible if delinquency-related outcomes, includingofficial and non-official (self-report or third-party reporting) measures of delinquency werereported.Data collection and analysisThis study used meta-analysis to synthesize results across studies. This method involvedsystematic coding of study features and conversion of study findings into effect sizesreflecting the direction and magnitude of any police-led diversion effect. There were 19independent evaluations across the 14 primary documents coded for this review. From this,we coded 67 effect sizes of delinquent behavior post diversion across 31 diversion-traditionalprocessing comparisons. We analyzed these comparisons using two approaches. The firstapproach selected a single effect size per comparison based on a decision rule and the secondused all 67 effect sizes, nesting these within comparison condition and evaluation design.ResultsThe general pattern of evidence is positive, suggesting that police-led diversion modestlyreduces future delinquent behavior of low-risk youth relative to traditional processing.Authors’ conclusionsThe findings from this systematic review support the use of police-led diversion for low-riskyouth with limited or no prior involvement with the juvenile justice system. Thus, policedepartments and policy-makers should consider diversionary programs as part of the mix ofsolutions for addressing youth crime